We are told:
- “...We are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end.” (Hebrews 3:13-14).
- "Keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life." (Jude 1:21).
- "...be thou faithful unto death, and I will give thee a crown of life." (Revelation 2:10).
We are told to:
- Continue in the grace of God (Acts of the Apostles 13:43).
- Continue in the faith (Acts of the Apostles 14:22) (Colossians 1:23).
- Continue in his goodness, otherwise we can be cut off (just like the Jews were cut off) (Romans 11:21-22).
We are also told...
John 10.
27 My sheep know my voice, and I know them. They follow me,
28 and I give them eternal life, so that
they will never be lost. No one can snatch them out of my hand.
29 My Father gave them to me, and he is greater than all others. No one can snatch them from his hands,
30 and I am one with the Father.
We are also told...
Jude 1
24 Now
unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy,
25 To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen.
We are also told...
Romans 8
I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come,
39 Nor height, nor depth, nor any other creature,
shall be able to separate us from the love of God, which is in Christ Jesus our Lord.
We are also told...
1 Thes 5
23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
24
Faithful is he that calleth you, who also will do it.
We are also told...
Truly, truly, I say to you, whoever hears my word and believes him who sent me has eternal life.
He does not come into judgment, but has passed from death to life.
We are also told...
And this is the testimony, that God gave us eternal life, and this life is in his Son. Whoever has the Son has life; whoever does not have the Son of God does not have life. I write these things to you who believe in the name of the Son of God,
that you may know that you have eternal life.
I could go on... There are about 100 verses supporting assurance of salvation.
In a lot of cases - verses suggesting the contrary are addressed to the church which had a mix of true believers and the unsaved. The warning then was to encourage the latter to press in to real faith and salvation.